add_host.log shows the following error :-
[05/26/2020 14:28:28] Return code: 0
[05/26/2020 14:28:28] CS host (VIOM-HOST-NAME) is resolvable
[05/26/2020 14:28:28] Trying to figure out if host is already part of the domain
[05/26/2020 14:28:28] Executing: "C:\Program Files\Veritas\VRTSsfmh\bin\xprtlc.exe" -u nobody -l https://localhost:5634/agent/domain/enum
[05/26/2020 14:28:29] ADD_HOST_SEND_CRED_MH
[05/26/2020 14:28:29] {"JOB":{"RETURNCODE":0,"ERROR":"Success","NAME":"add_host","OUTPUT":"ADD_HOST_SEND_CRED_MH","STATE":"SUCCESS","PROGRESS":30}}
[05/26/2020 14:28:29] Output: HTTP/1.1 403 Forbidden
403 Forbidden
[05/26/2020 14:28:29] Return code: 1024
[05/26/2020 14:28:29] fancy_die
[05/26/2020 14:28:29] ADD_HOST_CRED_PUSH_FAILED
[05/26/2020 14:28:29] fancy_dead
GUI: Error V-383-50513-5749 Could not contact managed host.

5634 (TCP) port is not open for hosts to communicate to and from MS via the xprtld daemon
Check whether the xprtld process is running or not managed host.
Run the following command on MH:
ps -ef | grep xprtld
Check firewall ports: 5634, 14161 ( port needs to be open on both MS and MH bi-directionally )
i.e :
curl -v telnet://IP of MH:5634 and curl -v telnet://IP of CMS:5634
curl -v telnet://IP of MH:14161 and curl -v telnet://IP of SMS:14161
Check xprtld process on MH:
ps -eaf | grep xprtld
Try starting xprtld on MH
/opt/VRTSsfmh/adm/xprtldctrl start
Check xprtl connectivity from MH to MS:
/opt/VRTSsfmh/bin/xprtlc -u "root" -l https://MS-hostname:5634/world/getvitals
Check xprtl connectivity from MS to MH:
/opt/VRTSsfmh/bin/xprtlc -u "root" -l https://MH-hostname:5634/world/getvitals